rp, if a new antenna still leaes it silent, the odds are the radio has a problem.
It may not be a total loss. First check, are you sure the squelch is turned down, that there are no odd settings that might have muted it?
Second thing to do--if you feel comfortable with it--is to unplug the radio, open it up, and carefully eyeball it. Many common failures are from a "cold solder joint" where something was not properly soldered in the radio. You can often see this (reading glasses help) and it could be the connection directly behind the antenna. Since it beeps and lights up, I assume the power connection and speaker connections are OK. Any chance there's a switch, or menu setting, that changes from "internal speaker" to "external speaker" and that someone got thrown?
You are looking for a hairline break in any of the solder connections, the silvery metal that is used to join up all the circuitry. If you DO find an obvious break in the solder, it can usually be repaired by just touching a $5soldering iron to it for a short while.
After that...you'd need to try finding a shop that either has free estimates, or other reasonable options. Often just "not feasible to repair" but sometimes, you can luck out.
Any chance you bought it with a credit card that gives you an extra year on the warranty, so you're still covered under that?